Improvement in grinding-stones for paint-mills



R. BYRNE. Grinding Stones for Paint Mills.

Nok 201,990; Patented April 2,1878..

INVENTOR.

' NjETERS PNOTGUTHOGRAFHER. WASHINGTON. D .C.

UNITED STATES PATENT QFFICE.

RICHARD BYRNE, OF BROOKLYN, NEW YORK, ASSIGNOR OF ONE-HALF HIS RIGHT TOJOSEPH J. MABRIN, OF NEW YORK CITY.

IMPROVEMENT IN GRINDING-STONES FOR PAINT-MILLS.

Specification forming part of Letters Patent No. 201,990, dated April 2,1878; application filed October 12, 1877.

To all whom it may concern.-

Be it known that I, Brennan BYRNE, of Brooklyn, in the county of Kingsand State of New York, have invented a certain new and useful.Improvement in Millstones, of which the following is a specification:

The said invention relates to the dressing or grooving of millstones,and particularly those used for grinding paint. In the ordinary methodof preparing the grinding-surfaces, the lower stone is first carefullydressed to a perfectly plane surface, and the upper one is made slightlyhollow for a short distance from the central opening, to facilitate theadmission between the stones of the material to be ground. A series ofnearly-radial grooves are then out, which are rectangular on one sideand slope or merge into the surface on the other, and which divide thesurface into a number of equal sections, called quarters, although theyusually number from eight to twelve. Each section is further groovedwith a number of similar furrows cut parallel to one of the radialborders; but those of no two adjacent sections are parallel to eachother.

In this ordinary method of arranging the furrows, and the lands or planesurfaces between them,the furrows that are made at the proper angle ordraft, or in the most efficient direction with relation to the center,are those which are the most efiective in enabling the centrifugal forceof the running stone to distribute and deliver the material over andfrom the entire grinding-surface. All the other furrows, in the degreethat they depart from this most effective relation, are proportionatelyinefficient; and the working effect of the corresponding lands iscorrespondingly diminished.

In addition to the loss and injury arising from the unequal andpartially imperfect action of the various parts of the stones, and theloss of power occasioned by running the surfaces that are not working attheir best rate of efficiency, there is a further loss and waste indressing down the inferior portions of the surfaces to restore them totheir original relation to those that are the best.

The object of my invention is to make all parts of the grinding-surfacesof the two stones alike effective; and it consists in combining achamber in the upper stone of about half its diameter, and a similargroove of the same size in the lower stone, with a series of straightand uniform furrows, the draft or obliquity of which is determined bythe nature of the material to be ground. The grinding-surface isrestricted to a comparatively narrow zone, the circular velocity of allparts of which is therefore approximately the same and this is 06-cupied by uniform series of similar furrows, the draft of each one ofwhich is the best for the work to be done.

For heavy material, like white-lead, the direction of the furrowsapproximates nearer to the radial position, or is tangential to asmaller circle than that which is best with a lighter material, likezinc-white. In changing, for different purposes, the draft of thefurrows, or the distance they would pass from the center of the stone ifprolonged or extended, there is less waste of the stone with thisuniform arrangement than there is when the surface is laid off inquarters or sections.

To enable others skilled in the arts to which it appertains to make anduse my invention, I will proceed to describe its construction andoperation with reference to the drawings.

Figure 1 is a vertical section of a pair of millstones, of whichthe'upper has a largecentral opening that reduces the grinding-surfaceto a comparatively narrow ring at the periphery, i11 which there is butlittle variation from the average action of the most effective part.Fig. 2 is a section of one side of the upper stone on a line with one ofits furrows, 0, which is cut deeper toward the center than theperiphery, to obviate any necessity for a departure from a plane surfaceon the face of the stone. Fig. 3 is a similar section of one side of thelower stone. Fig. 4 is a plan of the two stones, with a portion of theupper one broken away to show the furrows of the lower stone, of whichthe radial furrows I) run into the circular groove 0.

I claim as my invention- The inillstone-dress consisting of a series ofstraight furrows, a and b, in combination with the chamber in the upperstone and the circular groove 0 in the lower stone, substantially asdescribed.

RIGHARI) BYRNE. I

Witnesses WALTER PELL, WM. KEMZBLE HALL.

